Why is the newly replaced controller very noisy?

[DelValentina]

The reasons for the newly replaced controller being very noisy are as follows: Controller mismatch: The controller does not match well. Different controllers: The original was a sine wave controller (characterized by quiet operation), while the replacement is a square wave controller, which has particularly noticeable noise during startup. Different connection sequence: If the connection sequence between the controller and the motor is incorrect, it can cause issues such as no rotation, reverse rotation, lack of power at high speed, shaking, or forward rotation. Proper phase matching (adjusting the connection wire positions) is required. Additional considerations are as follows: Off-brand controllers: These not only consume more power but also exhibit significant power deficiencies. Generally, off-brand controllers are from unknown brands and appear poorly made in terms of craftsmanship. Refurbished controllers: Due to severe aging, even after refurbishment, these controllers typically have a shorter lifespan and are more prone to malfunctions, which can degrade the overall performance of the electric vehicle.